Torque wrench



Nov. 8, 1966 J. R. BAILEY 3,283,620

TORQUE WRENCH Filed Oct. 23, 1965 1/0 A. Bailey INVENTOR WHA NN 5 MaMAN/64L B Al /arms for A yb'am/ United States Patent ()fiice 3,283,620-Patented Nov. 8, 1966 3,283,620 TORQUE WRENCH Jay R. Bailey, WoodlandHills, Ca]if., assignor to McC ulloch Corporation, Los Angeles, Calif.,a corporation of Wisconsin Filed Oct. 23, 1965, Ser. No. 503,927 6Claims. (Cl. 81-524) This invention relates generally to hand tools andrelates more particularly to a torque wrench.

In many types of assembly work various parts are secured together byscrews and it is very important that these screws are of the propertightness. If the screws are too loose the parts will not be securedtogether properly and if they art tightened too much there is danger ofstripping the threads of the screws or the tapped openings into whichsaid screws are screwed or driven.

It is therefore an object of the present invention to provide a torquewrench that will overcome the above difficulty.

It is another object of the invention to provide a torque wrench withwhich the required close control of the tightness of the screws iseffected.

It is still another object of the invention to provide a torque wrenchof this character calibrated for effecting a desired predeterminedtightness of the screws.

It is a further object of the invention to provide a torque wrench ofthis character which indicates when the predetermined torque level hasbeen reached.

It is a still further object of the invention to provide a torque wrenchof this character with which fasteners or screws are uniformlytightened.

Another object of the invention is to provide a device of this characterthat is extremely simple in construction and that has a minimum numberof parts.

Still another object of the invention is to provide a device of thischaracter that is rugged and durable.

It is a further object of the invention to provide a device of thischaracter that may be manufactured at relatively low cost.

The characteristics and advantages of the invention are furthersufiiciently referred to in connection with the following detaileddescription of the accompanying drawings, which represent oneembodiment. After considering this example skilled persons willunderstand that many variations may be made without departing from theprincipals disclosed and I contemplate the employment of any structures,arrangements or modes of operation that are properly within the scope ofthe appended claims.

Referring to the drawings, which are for illustrative purposes only:

FIG. 1 is a perspective view of a wrench embodying the presentinvention;

FIG. 2 is an enlarged top plan view of same with the parts in the normalposition; and

FIG. 3 is an enlarged top plan view of the forward end of the wrenchwith the indicater parts showing that the predetermined torque level hasbeen reached.

Referring more particularly to the drawings, there is shown a wrenchembodying the present invention. The wrench is formed of a piece of barstock and includes a handle 10, at the forward end of which is aU-shaped loop, indicated generally at 11, and extending laterally of thehandle. Loop 11 includes an arm 12 that extends at right angles to theforward end of the handle, a closed arcuate end portion 14 that connectsthe outer end of arm 12 with the outer end of an arm 15 that issubstantially parallel to the arm 12, although the arm 12 is inclineddownwardly from the portion 14 so that the junction 13 of the arm 12with the handle is lower than the adjacent end of the arm 15.

From the end of arm 15 opposite the portion 14 which comprises theclosed end of the U-shaped part 11, there is a depending part 16 normalto the arm 15 and also normal to the handle 10.

The free end of the depending part 16 is of such shape as to engage thehead of a screw 18 for an assembly including the part 20.

The parts of the tool are integral and as shown the tool is of the samecross-sectional shape and size throughout its length. In this case thecross-sectional shape of the tool is hexagonal so that the free endportion of the part 16 is of the proper shape for operable reception inthe recess provided in the head of the screw 18 which is hexagonal incross-sectional shape, said screw 18 being of the Allen type. It is tobe understood, of course, that the free end portion of the part 16 maybe of other characteristics and the rest of the tool need not be of thesame shape and/or size as the free end portion that is engageable withthe screws to be tightened.

The stock used for the tool is resilient and the resilientcharacteristics thereof are of such predetermined value that when ascrew is tightened to the desired tightness the closed portion 14 of thewrench deflects and the ends of the arms 12 and 15 opposite the closedend portion 14 move toward each other. The length of the arm 12 is suchthat the depending part 16 is in the path of the junction part 13 as theends of the arms 12 and 15 opposite the part 14 move toward each otheras the screw is tightened and said part 13 closely approaches the part16, as shown in FIG. 3, or actually engages said part 16 when the screwhas been tightened to the desired amount.

The force applied to the handle 10 by the operator is then released,parts 12 and 16 of the tool returning to their normal positions as shownin FIGS. 1 and 2 and the tool removed from the recess or socket in thehead of the screw 18.

As pointed out above, the screw engaging portion of the wrench may be ofsome other shape and/ or size.

For example, the screw engaging portion of the part 16 may be a bladefor reception in the slot of a screw, or it may be a socket forpositioning over the head of a screw. The screw-engaging portion of thetool may, of course, be of still other configurations.

The invention and its attendant advantages will be understood from theforegoing description and it will be apparent that various changes maybe made in the form, construction and arrangement of the parts of theinvention without departing from the spirit or scope thereof orsacrificing its material advantages, the arrangements hereinbeforedescribed being merely by way of example, and I do not wish to berestricted to the specific forms shown or uses mentioned except asdefined in the accompanying claims, wherein various portions have beenseparated for clarity of reading and not for emphasis.

I claim:

1. In a torque wrench:

(A) a handle;

(B) a laterally extending loop having a pair of arms spaced apartlaterally relative to each other, one of said arms having one endconnected to the handle and having its other end connected to theadjacent end of the other arm by a resilient portion;

(C) and a screw-engaging part extending from the end of the other armopposite the part connecting the arms together and normal to the planeof the loop, there being a free end portion of the screw-engaging partadapted to operably engage a screw.

2. The invention defined by claim 1, wherein the tool is formed of asingle piece of bar stock.

3. The invention defined by claim 1, wherein the loop is U-shaped andthe arms thereof are normally substantially parallel to each other.

4. The invention defined by claim 1, wherein the tool References Citedby the Examiner is formed of bar stock that is hexagonal in crosssection. UNITED STATES PATENTS @253 ;gfiffilfiiffifififiii fiahifi fggggggg ggggg ggg gg 5;;

6. The invention defined by claim 1, wherein the end of 5 the armconnected to the handle and opposite the resilient FOREIGN TENTS portionis inclined in the direction of said screw-engaging 60,530 1/ 1943Denmark. part, said screw-engaging part being in the path of move-675,755 5/ 1939 Germany.

rnent of the handle connected end of said arm when the ends of the armsopposite the resilient portion are moved 1O WILLIAM FELDMAN PrimaryExammer' together. JAMES L. JONES, J 11., Examiner.

1. IN A TORQUE WRENCH: (A) A HANDLE; (B) A LATERALLY EXTENDING LOOPHAVING A PAIR OF ARMS SPACED APART LATERALLY RELATIVE TO EACH OTHER, ONEOF SAID ARMS HAVING ONE END CONNECTED TO THE HANDLE AND HAVING ITS OTHEREND CONNECTED TO THE ADJACENT END OF THE OTHER ARM BY A RESILIENTPORTION; (C) AND A SCREW-ENGAGING PART EXTENDING FROM THE END OF THEOTHER ARM OPPOSITE THE PART CONNECTING THE ARMS TOGETHER AND NORMAL TOTHE PLANE OF THE LOOP, THERE BEING A FREE END PORTION OF THESCREW-ENGAGING PART ADAPTED TO OPERABLY ENGAGE A SCREW.